Tissue thickness compensator comprising a plurality of layers

A fastener cartridge assembly for a surgical instrument, the fastener cartridge assembly comprising:

• a tissue thickness compensator comprising:
• a first compensation layer;
• a second compensation layer;
• and
• a first structure between said first compensation layer and said second compensation layer, wherein said first structure comprises a support, and wherein said support is configured to bow when said layer is compressed;
• a second structure positioned between said first compensation layer and said second compensation layer, wherein said first structure and said second structure are situated separately in between said first compensation layer and said second compensation layer and comprise different shapes;
• and
• a fastener cartridge comprising a fastener, wherein said fastener is moveable between an initial position and a fired position, and wherein said fastener is configured to pass through said first structure and said second structure when said fastener is moved to said fired position.

A fastener cartridge assembly for a surgical instrument, the fastener cartridge assembly comprising:

• a layer comprising:
• a first compensation layer;
• a second compensation layer;
• and
• a first structure positioned between said first compensation layer and said second compensation layer, wherein said first structure is selected from a group comprising:
• a centered, single-bend support beam;
• an off-centered, single-bend support beam;
• an elliptical support beam;
• a multi-bend support beam;
• and a symmetrical, dual-cantilevered support beam;
• a second structure positioned between said first compensation layer and said second compensation layer, wherein said first structure and said second structure comprise different shapes;
• and
• a fastener moveable between an initial position and a fired position, wherein said fastener is positioned to pass through and compress at least a portion of said layer.